The Internet of Things (IoT) is an umbrella term for smart things connected to the Internet. Precision agriculture is a related concept where connected sensors can be used to facilitate, e.g. more effective farming. At the same time, Bluetooth has been making advancements into IoT with the release of Bluetooth Low Energy (BLE) or Bluetooth smart as it is also known by. This thesis describes the development of a Bluetooth Low Energy moisture- and temperature sensor intended for use in an agricultural wireless sensor network system. The sensor was evaluated based on its effectiveness in agricultural environments and conditions such as weather, elevation and in different crop fields. Bluetooth Low Energy was chosen as the technology for communication by the supervising company due to its inherent support for mobile phone accessibility. Field tests showed that the sensor nodes were largely affected by greenery positioned between transmitter and receiver, meaning that these would preferably be placed above growing crops for effective communication. With ideal placement of the sensor and receiving unit, the signal would reach up to 100 m, meaning that a receiving unit would cover a circle area with radius 100 m. Due to Bluetooth being largely integrated in mobile devices it would mean that sensor data could easily be made accessible with a mobile app, rather than acquiring data from an online web server.